Question in Spring example "Petclinic"

[BillyW]

Hi,

First of all let's review this "petclinic-servlet.xml" file again:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http&#58;//www.springframework.org/dtd/spring-beans.dtd">

<beans>

	<bean id="viewResolver" class="org.springframework.web.servlet.view.ResourceBundleViewResolver">
		<property name="basename"><value>views</value></property>
	</bean>

	<bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
		<property name="exceptionMappings">
			<props>
				<prop key="org.springframework.dao.DataAccessException">dataAccessFailure</prop>
				<prop key="org.springframework.transaction.TransactionException">dataAccessFailure</prop>
			</props>
		</property>
	</bean>

	<bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
		<property name="mappings">
			<props>
				<prop key="/welcome.htm">clinicController</prop>
				<prop key="/vets.htm">clinicController</prop>
				<prop key="/owner.htm">clinicController</prop>
				<prop key="/findOwners.htm">findOwnersForm</prop>
				<prop key="/editOwner.htm">editOwnerForm</prop>
				<prop key="/addOwner.htm">addOwnerForm</prop>
				<prop key="/addVisit.htm">addVisitForm</prop>
				<prop key="/addPet.htm">addPetForm</prop>
				<prop key="/editPet.htm">editPetForm</prop>
			</props>
		</property>
	</bean>


	<bean id="clinicController" class="org.springframework.samples.petclinic.web.ClinicController">
		<property name="methodNameResolver"><ref local="clinicControllerResolver"/></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="clinicControllerResolver" class="org.springframework.web.servlet.mvc.multiaction.PropertiesMethodNameResolver">
		<property name="mappings">
		<props>
			<prop key="/welcome.htm">welcomeHandler</prop>
			<prop key="/vets.htm">vetsHandler</prop>
			<prop key="/owner.htm">ownerHandler</prop>
		</props>
		</property>
	</bean>

	<bean id="findOwnersForm" class="org.springframework.samples.petclinic.web.FindOwnersForm">
		<property name="formView"><value>findOwnersForm</value></property>
		<property name="selectView"><value>selectOwnerView</value></property>
		<property name="successView"><value>ownerRedirect</value></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="addOwnerForm" class="org.springframework.samples.petclinic.web.AddOwnerForm">
		<property name="formView"><value>ownerForm</value></property>
		<property name="successView"><value>ownerRedirect</value></property>
		<property name="validator"><ref local="ownerValidator"/></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="editOwnerForm" class="org.springframework.samples.petclinic.web.EditOwnerForm">
		<property name="formView"><value>ownerForm</value></property>
		<property name="successView"><value>ownerRedirect</value></property>
		<property name="validator"><ref local="ownerValidator"/></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="ownerValidator" class="org.springframework.samples.petclinic.validation.OwnerValidator"/>

	<bean id="addPetForm" class="org.springframework.samples.petclinic.web.AddPetForm">
		<property name="formView"><value>petForm</value></property>
		<property name="successView"><value>ownerRedirect</value></property>
		<property name="validator"><ref local="petValidator"/></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="editPetForm" class="org.springframework.samples.petclinic.web.EditPetForm">
		<property name="formView"><value>petForm</value></property>
		<property name="successView"><value>ownerRedirect</value></property>
		<property name="validator"><ref local="petValidator"/></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="petValidator" class="org.springframework.samples.petclinic.validation.PetValidator"/>

	<bean id="addVisitForm" class="org.springframework.samples.petclinic.web.AddVisitForm">
		<property name="formView"><value>visitForm</value></property>
		<property name="successView"><value>ownerRedirect</value></property>
		<property name="validator"><ref local="visitValidator"/></property>
		<property name="clinic"><ref bean="clinic"/></property>
	</bean>

	<bean id="visitValidator" class="org.springframework.samples.petclinic.validation.VisitValidator"/>

</beans>

The element

<property name="clinic"><ref bean="clinic"/></property>

was never been defined!

How it works?

I'm a beginer on Spring.
Any help would be appreciated!

BillyW
Thu Aug 26 10:42:29 2004 from China[/code]

[Rod Johnson]

Billy

There are two XML attributes for bean references: "local" (checked in XML, the bean definition must be in the same XML application context); and "bean" (the bean definition can be in an ancestor context).

The petclinic-servlet.xml file is a leaf context, that is the child of the contexts loaded by the WebApplicationContext, specified in web.xml. Thus it can see beans defined in applicationContext.xml and other contexts. The petclinic-servlet.xml file itself is concerned only with web tier functionality and "inherits" business object definitions.

[BillyW]

Got it! Thank you Rod!